I've recently acquired a ZX81 with a Memotech 16k and some tapes, Raiders/Bombers being one of them. Since the RF picture was garbage I immediately modded it to have composite out and it seems to work fine after that.

However, as I'm beginning to understand, loading from tapes can be quite tricky. I have an old school CRT TV that I'm using and I certainly get some reaction on screen when trying to load but nothing really happens after the supposed loading time.

The tape player I'm using is originally taken from one of my Spectrums and it lacks a tone and treble dial, could this be the reason for the tapes failing to load? Also, how do I know the memory pack is is connected and working properly?

Finally, I think I've read somewhere that you can use a standard Smartphone to load games from, but I haven't really found any instructions on how to do so.

If the zeddy switches on and you get a K there is a good chance the RAM pack is working.

There are more sophisticated checks but try this:-

DIM A(3000)

It should return 0:0 afterwards.

It is trying to dim an array of 3000 elements which more or less fills the RAM. If you try this without the RAM pack it will return an error number.

Loading is a dark art - the volume has to be perfect and the lack of fine control on yours may be a problem. If you have any 1K games try those first without the RAM pack attached. At least you only have to wait 20 to 30 seconds before you know it failed.

Also check the toggle switches on the back of the RAM pack. If it is not set correctly it won’t work (I found this out the hard way). On mine 1 is down, 2 and 3 are up, 4 is down.